When we visited with Erwitt during a signing on Wednesday at the Cole Haan flagship in Columbus Circle, he was wearing a necktie with cartoons of dog bones on it—dogs are, famously, one of Erwitt’s favorite subjects—and accepting from a waiter an hors d’oeuvre from Per Se, which catered the event. “I’m amoral!” he said affably, when we wondered whether the fact that all the photos in the book were shot on film represented some kind of ideological resistance to digital photography. “I don’t have any rules.”

For an old-school photographer, Erwitt is utterly unfazed by the proliferation of smartphone photos. “It hasn’t changed the art, but it’s certainly changed the density of pictures. But that’s not art. I mean, if you have a pencil, you’re not necessarily an artist,” he said. “I think they take pictures because it’s fun to take pictures—especially of your kids or your dog or your cat. No harm in that.”